Systems and methods for reducing temperature overshoot of a heating, ventilation, and air conditioning system

ABSTRACT

The disclosed technology includes systems and methods for reducing temperature overshoot of a heating, ventilation, and air conditioning (HVAC) system. The disclosed technology can include a thermostat having a temperature sensor and a controller. The controller can be configured to receive temperature data from the temperature sensor, determine whether a time since the heating cycle of the HVAC unit began is greater than or equal to a predetermined amount of time, and determine whether a current temperature is less than or equal to a low threshold temperature, the low threshold temperature being less than a target temperature. If the current temperature is less than or equal to the low threshold temperature, the controller can determine whether a capacity of the HVAC unit at the end of the heating cycle is greater than a threshold capacity and adjust a response setting of the thermostat by a predetermined adjustment amount.

FIELD OF TECHNOLOGY

The disclosed technology relates generally to systems and methods forreducing temperature overshoot of a heating, ventilation, and airconditioning (HVAC) system.

BACKGROUND

HVAC systems are commonly controlled using a thermostat, which generallyincludes a temperature sensor capable of detecting the temperature ofthe air in a climate-controlled space and a controller that is capableof controlling the HVAC system based on the detected temperature tomaintain the air temperature within a predetermined temperature range.To help ensure the temperature of the air in the climate-controlledspace is maintained within the predetermined temperature range,thermostats are generally installed on a wall in the climate-controlledspace such that the temperature sensor detects the temperature of theair in the climate-controlled space.

In some instances, the temperature sensor of the thermostat can detect atemperature of the air near the thermostat that is not representative ofthe temperature of the rest of the air within the climate-controlledspace. For example, if the thermostat is installed too closely to asupply air vent or a return air vent, the detected temperature of theair may be different from the temperature of the air in the rest of theclimate-controlled space. This can happen, for example, if thethermostat detects the temperature of the air that is supplied from anair duct that passes through a space that is not climate controlled(e.g., an attic, a crawl space, within the walls of a home, etc.). Whenthe HVAC system is operating in a heating mode, the stagnant air withinthe air duct can be substantially cooler than the temperature of the airwithin the climate-controlled space. Alternatively, when the HVAC systemis in a cooling mode, the stagnant air within the air duct can besubstantially warmer than the temperature of the air within theclimate-controlled space. Regardless, the stagnant air (which has atemperature substantially different from the air within theclimate-controlled space) can be supplied from the air duct before theheated (or cooled) air is supplied from the HVAC system. Thus, when theHVAC system receives a start signal and begins circulating air to theclimate-controlled space, the column of cool (or warm) stagnant air fromthe air duct can be delivered near the thermostat, causing thethermostat to detect an air temperature that is lower (or higher) thanthe air temperature within the rest of climate-controlled space. Whenthis occurs, the controller of the thermostat will interpret thetemperature data as indicating that the temperature within theclimate-controlled space is much lower (or higher) than it actually isand begin outputting a greater amount of heated air (or cooled air) thanis actually required. In some cases, the thermostat can cause the HVACsystem to heat the climate-controlled space to more than five degreesabove (or below) the target temperature, resulting in an inefficient useof the HVAC system and an uncomfortable climate for an occupant of theclimate-controlled space.

Some existing thermostats include an adjustment mechanism, such as anadjustment screw for mechanical thermostats or a gain adjustment optionfor digital controllers, to help to alleviate the amount of overshootthat can occur as a result of the thermostat being installed in a lessthan ideal location. Unfortunately, existing systems require a user tomanually adjust the gain (e.g., by turning the adjustment screw on amechanical controller or by adjusting the gain on a digital controller)and then wait for a heating (or cooling) cycle to be completed beforethe effect of the adjustment can be observed. Adjusting the gain isgenerally an iterative process and can be time consuming, oftenrequiring multiple heating or cooling cycles to adjust the gain to theright setting. Furthermore, once the gain is adjusted, the response ofthe thermostat can drift over time, requiring additional manualadjustment by a user to ensure the thermostat and HVAC system properlyheat and cool the climate-controlled space.

What is needed, therefore, is a system and method of reducing the amountof temperature overshoot that can occur as a result of a thermostatdetecting an air temperature that is not representative of the airtemperature in the rest of the climate-controlled space to ensure theHVAC system properly heats or cools the climate-controlled space. Theseand other problems are addressed by the technology disclosed herein.

SUMMARY

The disclosed technology relates generally to systems and methods forreducing temperature overshoot of a heating, ventilation, and airconditioning (HVAC) system. The disclosed technology can include athermostat for an HVAC system. The thermostat can include a temperaturesensor configured to detect a temperature of air proximate thethermostat and a controller. The controller can be configured to receivetemperature data from the temperature sensor and determine whether anamount of time since a heating cycle of an HVAC unit began is greaterthan or equal to a predetermined amount of time.

In response to determining that the amount of time since the heatingcycle began is greater than or equal to the predetermined amount oftime, the controller can determine whether a current temperature is lessthan or equal to a low threshold temperature. The low thresholdtemperature can be less than a target temperature. Alternatively, thelow threshold temperature can be less than a low turn-on temperature. Inresponse to determining that the current temperature is less than orequal to the low threshold temperature, the controller can determinewhether a capacity of the HVAC unit at the end of the heating cycle isgreater than a threshold capacity. In response to determining that thecapacity of the HVAC unit at the end of the heating cycle is greaterthan the threshold capacity, the controller can adjust a responsesetting of the thermostat by a predetermined adjustment amount.

The response setting can be a gain setting of the controller andadjusting the response setting of the thermostat by the predeterminedadjustment amount can include adjusting the gain setting of thecontroller by a fixed amount. Alternatively, adjusting the responsesetting of the thermostat by the predetermined adjustment amount caninclude adjusting the gain setting of the controller by an amount thatis proportional to the amount that the capacity of the HVAC unit at theend of the heating cycle is greater than the threshold capacity.

The response setting can be a time setting of the controller. Adjustingthe response setting of the thermostat by the predetermined adjustmentamount can include adjusting the time setting of the controller by afixed amount. Alternatively, adjusting the response setting of thethermostat by the predetermined adjustment amount can include adjustingthe time setting of the controller by an amount that is proportional tothe amount that the capacity of the HVAC unit at the end of the heatingcycle is greater than the threshold capacity. The predetermined amountof time can be about two minutes.

In response to determining that the current temperature is less than orequal to the low threshold temperature, the controller can determinewhether the current temperature at the end of the heating cycle isgreater than or equal to a high overshoot temperature. In response todetermining that the current temperature at the end of the heating cycleis greater than or equal to the high overshoot temperature, thecontroller can adjust the response setting of the thermostat by thepredetermined adjustment amount. Adjusting the response setting of thethermostat by the predetermined adjustment amount can include adjustingthe gain setting of the controller by an amount that is proportional tothe amount that the current temperature at the end of the heating cycleis greater than the high overshoot temperature. Alternatively, adjustingthe response setting of the thermostat by the predetermined adjustmentamount can include adjusting the time setting of the controller by anamount that is proportional to the amount that the current temperatureat the end of the heating cycle is greater than the high overshoottemperature.

The controller can be further configured to determine whether an amountof time since a cooling cycle of an HVAC unit began is greater than orequal to the predetermined amount of time. In response to determiningthat the amount of time since the cooling cycle began is greater than orequal to the predetermined amount of time, the controller can determinewhether the current temperature is greater than or equal to a highthreshold temperature. The high threshold temperature can be greaterthan the target temperature. Alternatively, the high thresholdtemperature can be greater than a high turn-on temperature. In responseto determining that the current temperature is greater than or equal tothe high threshold temperature, the controller can determine whether thecapacity of the HVAC unit at the end of the cooling cycle is greaterthan the threshold capacity. In response to determining that thecapacity of the HVAC unit at the end of the cooling cycle is greaterthan the threshold capacity, the controller can adjust a responsesetting of the thermostat by a predetermined adjustment amount.

In response to determining that the current temperature is less than orequal to the low threshold temperature, the controller can be configuredto determine whether the current temperature at the end of the heatingcycle is greater than or equal to a high overshoot temperature. Inresponse to determining that the current temperature at the end of theheating cycle is greater than or equal to the high overshoottemperature, the controller can be configured to adjust the responsesetting of the thermostat (e.g., a gain setting of the controller or atime setting of the controller) by the predetermined adjustment amount.

Additional features, functionalities, and applications of the disclosedtechnology are discussed herein in more detail.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate multiple examples of thepresently disclosed subject matter and serve to explain the principlesof the presently disclosed subject matter. The drawings are not intendedto limit the scope of the presently disclosed subject matter in anymanner.

FIG. 1A illustrates an example HVAC system, in accordance with thedisclosed technology.

FIG. 1B illustrates an example thermostat of the HVAC system, inaccordance with the disclosed technology.

FIG. 2 is a logic diagram illustrating an example method ofautomatically adjusting a response setting of a thermostat of an HVACsystem when in a heating mode, in accordance with the disclosedtechnology.

FIG. 3 is a logic diagram illustrating an example method ofautomatically adjusting a response setting of a thermostat of an HVACsystem when in a cooling mode, in accordance with the disclosedtechnology.

DETAILED DESCRIPTION

The disclosed technology relates generally to systems and methods forreducing temperature overshoot of a heating, ventilation, and airconditioning (HVAC) system. As will become apparent throughout thisdisclosure, the disclosed technology can determine when the gain or atime setting on a thermostat should be adjusted and then automaticallyadjust the gain or time setting to ensure the HVAC system properly heatsand/or cools the ventilated space. The disclosed technology can beuseful, for example, when the thermostat of an HVAC has been installedin a location that is subject to temperature changes that may not berepresentative of the temperature of the air in all or a substantialportion (e.g., the majority) of the ventilated space (e.g., when thethermostat is installed too closely to an element that could negativelyimpact the accuracy of a temperature measurement being representative ofthe temperature of the overall space, such as a location at or near asupply air vent, return air vent, door, window, or equipment). Thedisclosed technology can determine that the gain or time setting shouldbe adjusted to prevent the system from overshooting the shutofftemperature and causing the air temperature within the ventilated spaceto be at an uncomfortable level.

Although certain examples of the disclosed technology are explained indetail herein, it is to be understood that other examples, embodiments,and implementations of the disclosed technology are contemplated.Accordingly, it is not intended that the disclosed technology is limitedin its scope to the details of construction and arrangement ofcomponents expressly set forth in the following description orillustrated in the drawings. The disclosed technology can be implementedin a variety of examples and can be practiced or carried out in variousways. In particular, the presently disclosed subject matter is describedin the context of being a system and method for automatically adjustingthe gain on a thermostat of an HVAC system. The present disclosure,however, is not so limited, and can be applicable in other contexts. Thepresent disclosure, for example and not limitation, can include othersystems utilizing a thermostat such as automotive HVAC systems, waterheater systems, industrial fluid heating or cooling systems, or anyother system configured to heat or cool a fluid by utilizing athermostat to control the temperature. Such implementations andapplications are contemplated within the scope of the presentdisclosure. Accordingly, when the present disclosure is described in thecontext of being a system and method for automatically adjusting thegain or time setting on a thermostat of an HVAC system, it will beunderstood that other implementations can take the place of thosereferred to.

It should also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferences unless the context clearly dictates otherwise. References toa composition containing “a” constituent is intended to include otherconstituents in addition to the one named.

Also, in describing the examples, terminology will be resorted to forthe sake of clarity. It is intended that each term contemplates itsbroadest meaning as understood by those skilled in the art and includesall technical equivalents which operate in a similar manner toaccomplish a similar purpose.

Ranges may be expressed herein as from “about” or “approximately” or“substantially” one particular value and/or to “about” or“approximately” or “substantially” another particular value. When such arange is expressed, the various examples of the disclosed technologyincludes from the one particular value and/or to the other particularvalue. Further, ranges described as being between a first value and asecond value are inclusive of the first and second values. Likewise,ranges described as being from a first value and to a second value areinclusive of the first and second values.

Herein, the use of terms such as “having,” “has,” “including,” or“includes” are open-ended and are intended to have the same meaning asterms such as “comprising” or “comprises” and not preclude the presenceof other structure, material, or acts. Similarly, though the use ofterms such as “can” or “may” are intended to be open-ended and toreflect that structure, material, or acts are not necessary, the failureto use such terms is not intended to reflect that structure, material,or acts are essential. To the extent that structure, material, or actsare presently considered to be essential, they are identified as such.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps or interveningmethod steps between those steps expressly identified. Moreover,although the term “step” can be used herein to connote different aspectsof methods employed, the term should not be interpreted as implying anyparticular order among or between various steps herein disclosed unlessand except when the order of individual steps is explicitly required.Further, the disclosed technology does not necessarily require all stepsincluded in the example methods and processes described herein. That is,the disclosed technology includes methods that omit one or more stepsexpressly discussed with respect to the examples provided herein.

The components described hereinafter as making up various elements ofthe disclosed technology are intended to be illustrative and notrestrictive. Many suitable components that would perform the same orsimilar functions as the components described herein are intended to beembraced within the scope of the disclosed technology. Such othercomponents not described herein can include, but are not limited to, forexample, similar components that are developed after development of thepresently disclosed subject matter.

Although the term “air” is used throughout this specification, it is tobe understood that other fluids may take the place of the term “air” asused herein. Therefore, although described as systems and methods for anHVAC system, it is to be understood that the system and methodsdescribed herein can apply to fluids other than air. Further, it is alsoto be understood that the term “air” can replace the term “fluid” asused herein unless the context clearly dictates otherwise.

As used herein, the term “target temperature” can be a temperature thatis a preferred temperature of an occupant of the climate-controlledspace (e.g., 72° F.), such as a user-inputted set point for the HVACsystem. As will be appreciated, the HVAC system described herein can beconfigured to maintain a temperature of the air within theclimate-controlled space based on the target temperature. In otherwords, the HVAC system will attempt to keep the temperature of the airwithin the climate-controlled space to within an acceptable range of thetarget temperature. Furthermore, the term “turn-on temperature” can be atemperature at which the thermostat will determine that the HVAC systemshould turn on to heat or cool the climate-controlled space (e.g., thetemperature at which the thermostat determines that the air within theclimate-controlled space is getting too cold (when in a heating mode) ortoo hot (when in a cooling mode)). Similarly, the term “turn-offtemperature” can refer to a temperature at which the thermostat willdetermine that the HVAC system should turn off and cease heating orcooling the climate-controlled space (e.g., the temperature at which thethermostat determines that the air within the climate-controlled spaceis reaching an acceptable temperature).

Referring now to the drawings, in which like numerals represent likeelements, examples of the present disclosure are herein described. FIG.1A illustrates an example HVAC system 100, in accordance with thedisclosed technology. The HVAC system 100 can be configured to controlthe temperature of air within a climate-controlled space 102 (e.g., ahome, a commercial building, a storage unit, a vehicle, etc.) bycirculating heated or cooled air from an HVAC unit 114, through a supplyair vent 104, through the climate-controlled space 102, and then back tothe HVAC unit 114 through a return air vent 106 and ductwork 112. TheHVAC unit 114 can be any type of HVAC unit including, but not limitedto, a split system, a hybrid split system, a mini-split system, apackaged heating and air system, a gas-fired furnace, a heat pump, andelectric heater, an evaporative cooler, or any other type of HVAC unitthat can heat and/or cool air circulated to the climate-controlled space102. Thus, although described as an HVAC unit 114 throughout thisdisclosure, one of skill in the art will appreciate that the disclosedtechnology can include any system configured heat and/or cool air thatis circulated through the climate-controlled space 102. Furthermore,although described herein as having ductwork 112, the HVAC system 100can be a ductless HVAC system 100 having only a supply air vent 104 anda return air vent 106.

The HVAC system 100 can include a thermostat 120 that can be configuredto detect a temperature of the air within the climate-controlled space102 and output instructions to the HVAC unit 114 to supply either heatedor cooled air to the climate-controlled space. In this way, thethermostat 120 can help to ensure the temperature of the air within theclimate-controlled space is maintained within a comfortable temperaturerange. As described previously, the thermostat 120 can be installed on awall of the climate-controlled space 102 or be otherwise installed in alocation where the thermostat 120 can detect a temperature of the airwithin the climate-controlled space 102. As depicted in FIG. 1A, in someinstances the thermostat 120 can be installed in a location that isproximate the supply air vent 104. When this is the case, the thermostat120 can sometimes detect a temperature of the supply air 108 deliveredfrom the supply air vent 104 that is not an accurate reflection of thetemperature of the air within the remainder of the climate-controlledspace 102. In other instances, the thermostat 120 can be installed inany other location that can negatively impact the accuracy of thethermostat's temperature measurements being representative of thetemperature of the overall space 102 (e.g., a location proximate thereturn air vent 106, proximate a door, proximate a window, or at anotherlocation that is subject to occasionally causing air proximate thethermostat 120 to have a temperature that is different from all or asubstantial portion (e.g., the majority) of the air within theclimate-controlled space 102). When the thermostat 120 is installed inone such location subject to temperature fluctuations that are notrepresentative of the overall space, the thermostat 120 can cause theHVAC unit 114 to supply a greater amount of heated or cooled air than isnecessary, as described previously. Thus, when the thermostat 120 isinstalled in a less than ideal location, the thermostat 120 cansometimes return non-representative temperature values, causing the HVACunit 114 to overshoot the shutoff temperature by several degreesFahrenheit and thereby creating an uncomfortable climate for an occupantof the climate-controlled space 102.

FIG. 1B illustrates an example thermostat 120 of the HVAC system 100, inaccordance with the disclosed technology. The thermostat 120 can includea temperature sensor 122 and a controller 130 configured to receivetemperature data from the temperature sensor 122. The temperature sensor122 can be integrated with the thermostat 120 as shown in FIG. 1B, orthe temperature sensor can be remote from the thermostat 120. No matterthe configuration, the temperature sensor 122 can be configured todetect a temperature of the air proximate the temperature sensor 122 andoutput temperature data to the controller 130. As will be appreciated byone of skill in the art with the benefit of this disclosure, if thetemperature sensor 122 is installed in a location where it can detect atemperature of air that is not representative of all or a substantialportion (e.g., the majority) of the air within the climate-controlledspace 102, the temperature sensor 122 will output data to the controller130 that may inaccurately represent the temperature of the air withinthe climate-controlled space 102. Accordingly, the methods and systemsdescribed herein are configured to reduce a temperature overshoot thatcan occur as a result of the temperature sensor 122 outputtingtemperature data to the controller 130 that is not representative of thetemperature of all or a substantial portion (e.g., the majority) of theair within the climate-controlled space 102.

The temperature sensor 122 can be any type of temperature sensor capableof detecting the temperature of the air proximate the temperature sensor122 and providing temperature data indicative of the air temperature tothe controller 130. For example, the temperature sensor 122 can be athermocouple, a resistor temperature detector, a thermistor, an infraredsensor, a semiconductor, or any other type of sensor which would beappropriate for a given use or application.

The controller 130 of the thermostat 120 can have a memory 132, aprocessor 134, and a communication interface 136. The controller 130 canbe a computing device configured to receive data, determine actionsbased on the received data, and output a control signal instructing oneor more components of the HVAC system 100 to perform one or moreactions. The controller 130 can be integrated with the thermostat 120 inthe same housing or enclosure. One of skill in the art, however, willappreciate that the controller 130 can be installed in any location,provided the controller 130 is in communication with at least some ofthe components of the HVAC system 100 (e.g., at least the temperaturesensor 122 and the HVAC unit 114). For example, the controller 130 canbe remote from the temperature sensor 122 and from the user interface138. Furthermore, the controller 130 can be configured to send andreceive wireless or wired signals and the signals can be analog ordigital signals. The wireless signals can include Bluetooth™, BLE, WiFi™ZigBee™, infrared, microwave radio, or any other type of wirelesscommunication as may be suitable for the particular application. Thehard-wired signal can include any directly wired connection between thecontroller 130 and the other components. Alternatively, the componentscan be powered directly from a power source and receive controlinstructions from the controller 130 via a digital connection. Thedigital connection can include a connection such as an Ethernet or aserial connection and can utilize any suitable communication protocolfor the application such as Modbus, fieldbus, PROFIBUS, SafetyBus p,Ethernet/IP, or any other suitable communication protocol for theapplication. Furthermore, the controller 130 can utilize a combinationof wireless, hard-wired, and analog or digital communication signals tocommunicate with and control the various components. One of skill in theart will appreciate that the above configurations are given merely asnon-limiting examples and the actual configuration can vary depending onthe particular application.

The controller 130 can include a memory 132 (e.g., a computer-readablemedium) that can store a program and/or instructions associated with thefunctions and methods described herein and can include one or moreprocessors 134 configured to execute the program and/or instructions.The memory 132 can include one or more suitable types of memory (e.g.,volatile or non-volatile memory, random access memory (RAM), read onlymemory (ROM), programmable read-only memory (PROM), erasableprogrammable read-only memory (EPROM), electrically erasableprogrammable read-only memory (EEPROM), magnetic disks, optical disks,floppy disks, hard disks, removable cartridges, flash memory, aredundant array of independent disks (RAID), and the like) for storingfiles including the operating system, application programs (including,for example, a web browser application, a widget or gadget engine, andor other applications, as necessary), executable instructions and data.One, some, or all of the processing techniques or methods describedherein can be implemented as a combination of executable instructionsand data within the memory.

The controller 130 can also have a communication interface 136 forsending and receiving communication signals between the variouscomponents. Communication interface 136 can include hardware, firmware,and/or software that allows the processor(s) 134 to communicate with theother components via wired or wireless networks, whether local or widearea, private or public, as known in the art. Communication interface136 can also provide access to a cellular network, the Internet, a localarea network, or another wide-area network as suitable for theparticular application.

Additionally, the controller 130 can have or be in communication with auser interface 138 for displaying system information and receivinginputs from a user. The user interface 138 can be integrated with thecontroller 130 in a housing or enclosure of the thermostat 120 or be aremotely controlled device such as a mobile device. The user, forexample, can view system data on the user interface 138 and input dataor commands to the controller 130 via the user interface 138. Forexample, the user can view temperature settings, temperature thresholdsettings, gain settings, time settings, etc. on the user interface 138and provide inputs to the controller 130 via the user interface 138 tochange any of the settings.

The controller 130 can be configured to receive temperature data fromthe temperature sensor 122, determine actions based on the detectedtemperature and stored temperature setpoints, and output control signalsto the HVAC unit 114. For example, as will be described in greaterdetail herein, the controller 130 can be configured to determine whetherto adjust the gain setting stored in the memory 132 based at least inpart on data received from the temperature sensor 122, the HVAC unit114, and/or other components of the HVAC system 100. As will becomeapparent throughout this disclosure, the controller 130 can beconfigured to control the HVAC system 100 in accordance with one or moreof the example methods described in relation to FIG. 2 and FIG. 3 .

FIG. 2 is a logic diagram illustrating an example method ofautomatically adjusting a response setting (e.g., the gain, a timesetting) of the thermostat 120 of the HVAC system 100 when in a heatingmode, in accordance with the disclosed technology. The method 200described herein can reduce the amount of temperature overshoot whichcan occur as a result of the thermostat 120 being installed in alocation where it can detect a temperature of the air that is notrepresentative of all or a substantial portion (e.g., the majority) ofthe air within the climate-controlled space 102. For example, the method200 can help to reduce the amount of temperature overshoot that mayoccur as a result of the thermostat 120 being installed too closely tothe supply air vent 104 (e.g., as shown and described in relation toFIG. 1A), the return air vent 106, a door, a window, etc. Thus, themethod 200 shown and described in relation to FIG. 2 can help ensure theHVAC unit 114 does not supply too much heated air and, therefore,overheat the climate-controlled space 102.

The method 200 of operating the HVAC system 100 can include starting alogic sequence by receiving a start signal or by initiating the method200 (e.g., as power is received to the controller 130). The method 200can include determining 202 whether the heater (e.g., HVAC unit 114) ison. For example, determining 202 whether the heater is on can includedetermining whether a start signal has been sent by the thermostat 120to the HVAC unit 114, detecting that the heater has begun to heat theair, detecting that a furnace of the heater has ignited, or the like. Inother words, determining 202 whether the heater is on can includedetermining whether the heater has been instructed to heat, is beginningto heat, and/or is currently heating, the air within the HVAC unit todeliver the heated air to the climate-controlled space 102. If theheater is not on, the method 200 can include continuing to determine 202if the heater is on (e.g., continuously, at predetermined intervals).

If the heater is on, the method 200 can include determining 204 whetheran elapsed time since the heater turned on is greater than or equal to apredetermined time. For example, the method 200 can include measuring anamount of time since the heater was turned on and comparing the measuredtime to a predetermined time (i.e., a predetermined amount of time). Thepredetermined time can be, for example, a predetermined amount of timesince the heater was first turned on after which the HVAC unit 114 islikely to begin circulating the air to the climate-controlled space 102.For example, if the HVAC unit 114 is likely to begin circulating theheated air to the climate-controlled space 102 within two minutes, thepredetermined time can be about two minutes. In this way, the method 200can ensure that a temperature detected after the predetermined time isrepresentative of the temperature of the air proximate the thermostat120 after the HVAC unit 114 has begun to circulate the heated air to theclimate-controlled space 102. The predetermined time, for example, canbe thirty seconds, one minute, two minutes, three minutes, four minutes,five minutes, or any greater or lesser time depending on the particularconfiguration. If the elapsed time is not greater than or equal to thepredetermined time, the method 200 can include continuing to determine204 whether the elapsed time is greater that or equal to thepredetermined time (e.g., continuously, at predetermined intervals).

If the elapsed time is greater than or equal to the predetermined time,the method 200 can include determining 206 whether the currenttemperature (e.g., the temperature of the air proximate the thermostat120 at the time the temperature of the air is detected) is less than orequal to a low threshold temperature. In other words, the method 200 caninclude checking a temperature of the air proximate the thermostat 120at a time after the heater has been able to operate for thepredetermined amount of time. If the current temperature is less than orequal to the low threshold temperature, this can be an indication thatthe thermostat 120 can be installed in a location that is notrepresentative of the temperature of all or a substantial portion (e.g.,the majority) of the air within the climate-controlled space 102. Forexample, the current temperature can be less than or equal to the lowthreshold temperature as a result of cool air from an air duct beingdirected toward the thermostat 120 from the supply air vent 104 beforethe heated air is supplied from the air duct.

The low threshold temperature can be a fixed temperature such as atemperature that is a predetermined amount less than the targettemperature (e.g., 5° F. below the target temperature (67° F. if thetarget temperature is 72° F.), 3° F. below the target temperature (69°F. if the target temperature is 72° F.), etc.) or a predetermined amountless than the low turn-on temperature (e.g., 5° F. below the low turn-ontemperature (65° F. if the low turn-on temperature is 70° F., 3° F.below the low turn-on temperature (67° if the low turn-on temperature is70° F.), etc.). Alternatively, the low threshold temperature can bevariable and can be based on the current temperature at the time theheater is first turned on. For example, if the current temperature atthe time the heater is first turned on was 65° F., the low thresholdtemperature can be 3° F. below the current temperature at the time theheater first turned on (i.e., 62° F.). To illustrate, a targettemperature of a thermostat 120 may be set to 72° F. with a turn-ontemperature of 70° F. In some cases, the HVAC system 100 may be turnedon with the temperature of the air in the climate-controlled space 102being less than the turn-on temperature (e.g., the temperature of theair in the climate-controlled space 102 can be at 68° F. when the HVACsystem 100 is first turned on for the winter season). When the HVACsystem 100 is turned on and the current temperature is less than theturn-on temperature, the thermostat 120 will monitor whether the airtemperature continues to fall to the low threshold temperature (e.g.,62° F.) after the predetermined time. In other words, if the temperaturecontinues to fall more than a predetermined amount (3° F. in thisexample) after the heater has turned on, this can be an indication thatthe thermostat 120 is installed in a less than ideal location. If thecurrent temperature is greater than the low threshold temperature, themethod can include finishing the heating cycle 207 and returning to thebeginning of the method 200 to determine 202 if the heater is on.

If the temperature is less than or equal to the low thresholdtemperature, the method 200 can include determining 208 whether theheating cycle is complete. Determining 208 whether the heating cycle iscomplete can include determining whether the heater has completed aheating cycle and has shut down. Alternatively, or in addition, thedetermining 208 whether the heating cycle is complete can includedetermining whether the current temperature is greater than or equal tothe turn-off temperature. If the heating cycle is not complete, themethod 200 can include continuing to check whether the heating cycle iscomplete (e.g., continuously, at predetermined interval s).

If the heating cycle is complete, the method 200 can include determining210 whether the capacity of the HVAC unit 114 at the time the heatingcycle was completed is greater than or equal to a threshold capacity.The threshold capacity can be a predetermined amount or percentage ofcapacity that is greater than the minimum capacity (e.g., 20%, 25%, 30%,50%, etc. above the minimum capacity of the HVAC unit 114). The capacitycan be a measure of the total heat output of the HVAC unit 114 when itis operating.

As will be appreciated by one of skill in the art, as an HVAC unit 114approaches the turn-off temperature under normal conditions, the HVACunit 114 will begin to ramp down the heat output of the HVAC unit 114(e.g., the total capacity at which the HVAC unit is operating) to avoidoverheating the climate-controlled space 102 once the HVAC unit 114reaches the turn-off temperature. For example, if the HVAC unit 114 hasa target temperature of 72° F. and a turn-off temperature of 73° F., theHVAC unit 114 can be configured to begin ramping down the capacity ofthe HVAC unit 114 to a minimum once the current temperature reaches72.5° F. such that the HVAC unit 114 will not overshoot the shut offtemperature by several degrees. Thus, if the capacity of the HVAC unit114 is greater than the threshold capacity at the time the HVAC unit 114shut down, this can be an indication that the HVAC unit 114 wasoutputting too much heat capacity, potentially as a result of thethermostat 120 detecting a temperature of the air proximate thethermostat 120 that was not representative of all or a substantialportion (e.g., the majority) of the air within the climate-controlledspace 102.

If the controller 130 determines 210 that the capacity of the HVAC unitis greater than or equal to the threshold capacity, the method 200 caninclude adjusting 214 a response setting of the thermostat 120 by apredetermined amount (e.g., a gain setting or a time setting of thethermostat), as will be described in greater detail herein, andreturning to the beginning of the method 200 to determine 202 whetherthe heater is on. If the controller 130 determines that the capacity ofthe HVAC unit is less than the threshold capacity, the method 200 caninclude determining 212 whether the current temperature at the time theheating cycle was completed is greater than or equal to a high overshoottemperature. The high overshoot temperature can be a predeterminedtemperature that is indicative of the HVAC unit 114 providing too muchheated air to the climate-controlled space 102. For example, if theturn-off temperature is 73° F., the high overshoot temperature can be75° F. or some other predetermined temperature suitable for theapplication. In other words, if the current temperature at the end ofthe heating cycle (or some time after the heating cycle has completed)is greater than the high overshoot temperature, it is possible that thethermostat 120 detected a temperature during the heating cycle that wasnot representative of the temperature of all or a substantial portion(e.g., the majority) of the air within the climate-controlled space 102(hence, why the HVAC unit 114 provided too much heated air).

If the controller 130 determines that the current temperature at the endof the heating cycle is less than the high overshoot temperature, themethod 200 can include returning to the beginning and determining 202whether the heater is on. If the controller 130 determines that thecurrent temperature at the end of the heating cycle is greater than orequal to the high overshoot temperature, the method 200 can includeadjusting 214 a response setting of the thermostat 120 by apredetermined amount (e.g., a gain setting or a time setting of thethermostat) and returning to the beginning and determining 202 whetherthe heater is on.

As will be appreciated by one of skill in the art, some controllers ofthermostats are equipped with proportional, integral, derivative (PID)controllers or other similar control schemes that include a gain settingto control a response of the thermostat and HVAC unit (e.g., an“anticipator” setting). By adjusting the gain in a first direction(i.e., increasing the gain value), the controller 130 will cause theHVAC unit 114 to respond more quickly to a temperature change.Conversely, by adjusting the gain in a second direction (i.e.,decreasing the gain value), the controller 130 will cause the HVAC unit114 to respond more slowly to a temperature change. By adjusting thegain and continuing to check the response to the gain adjustment, thedisclosed technology can help to prevent temperature overshoot bycausing the controller 130 to respond more slowly to a temperaturechange thereby preventing the controller 130 from outputtinginstructions to increase the heating capacity if a low temperature isdetected soon after the HVAC unit 114 has begun to supply heated air.

On the other hand, some HVAC units include a controller 130 of thethermostat 120 that is configured to adjust a time setting of thevarious stages of the HVAC unit 114 (e.g., discrete staged equipmenthaving multiple, discrete heating or cooling stages) or individualheating or cooling cycles. By adjusting the time setting (i.e., thelength of time between each discrete heating or cooling stage or thelength of time between each heating or cooling cycle), the controller130 can similarly help to ensure the HVAC unit 114 does not provide toomuch heated air to the climate-controlled space 102. For example, if thethermostat 120 detects a low temperature soon after the HVAC unit 114has begun to supply heated air, adjusting the time setting to lengthenthe run time of a lower capacity discrete heating stage can, in turn,shorten a run time of a higher capacity discrete heating stage, therebyhelping to prevent the HVAC unit 114 from overheating theclimate-controlled space 102. Furthermore, increasing a time betweeneach heating or cooling cycle can help to prevent the HVAC unit 114 fromproviding heated (or cooled) air too frequently and ultimatelyoverheating (or overcooling) the climate-controlled space 102.

Adjusting 214 the response setting of the thermostat 120 can includeadjusting the response setting by a predetermined amount. For example,if the gain setting on the thermostat 120 has a range of values from 1to 10, the controller 130 can adjust the gain by a value of 1. Asanother example, if the gain setting has a range from 0-100%, thecontroller 130 can adjust the gain by a value of 5% or some otherpredetermined value suitable for the application. Similarly, if thecontroller 130 adjusts a time setting, the controller 130 can adjust thetime setting by 1 second, 5 seconds, 10 seconds, 30 seconds, 1 minute, 2minutes, 5 minutes, or any other predetermined amount of time suitablefor the application. Alternatively, the controller 130 can adjust theresponse setting by an amount proportional to the amount of overshootobserved. For example, the controller 130 can adjust the responsesetting by the amount that the capacity of the HVAC unit 114 at the endof the heating cycle is greater than the threshold capacity. Similarly,the controller 130 can adjust the response setting by an amount that isproportional to amount that the current temperature at the end of theheating cycle is greater than the high overshoot temperature. In thisway, the controller 130 can adjust the gain or time setting in greateramounts or smaller amounts as would be appropriate for the particularsituation. Furthermore, as will be appreciated by one of skill in theart, adjusting the gain can include increasing or decreasing the gain aswould be appropriate for the particular situation. Similarly, adjustingthe time setting can include increasing or decreasing a length of timebetween one or more stages as would be appropriate for the particularsituation.

FIG. 3 is a logic diagram illustrating an example method 300 ofautomatically adjusting a response setting of the thermostat 120 of theHVAC system 100 when in a cooling mode, in accordance with the disclosedtechnology. As will be appreciated, the method 300 can be substantiallysimilar to the method 200 except that the various elements correspond toa cooling cycle rather than a heating cycle. For example, the method 300can include determining 302 whether the air conditioning (AC) is turnedon. For example, determining 302 whether the AC is on can includedetermining whether a start signal has been sent by the thermostat 120to the HVAC unit 114, detecting that the AC has begun to cool the air,detecting whether a compressor of a refrigerant cycle is operating, etc.In other words, determining 302 whether the AC is on can includedetermining whether the AC has been instructed to cool, is beginning tocool, and/or is currently cooling, the air within the HVAC unit todeliver the cooled air to the climate-controlled space 102. If the AC isnot on, the method 300 can include continuing to determine 302 if the ACis on.

If the AC is on, the method 300 can include determining 302 whether anelapsed time since the AC has turned on is greater than or equal to apredetermined time. Determining 302 whether an elapsed time since the AChas turned on is greater than or equal to a predetermined time caninclude all of the same steps and/or features described in relation tofeature 202 of method 200. Furthermore, the predetermined time can bethe same as, or different from, the predetermine time described inrelation to feature 202 of method 200.

The method 300 can further include determining 306 whether the currenttemperature is greater than or equal to a high threshold temperature.For example, rather than the thermostat 120 detecting a low temperatureof air delivered from the supply air vent 104, as described in relationto feature 206, the thermostat 120 can detect a high temperature of theair delivered from the supply air vent 104 (e.g., when stagnant warm airis first delivered from an air duct that has passed through a warm atticbefore the cooled air is delivered). Similar to feature 206, the highthreshold temperature can be a fixed temperature based on either thetarget temperature or the turn-on temperature, or the high thresholdtemperature can be variable and be based on the current temperature atthe time the HVAC unit 114 is turned on. As will be appreciated by oneof skill in the art, unlike the low threshold temperature described inrelation to feature 206, the high threshold temperature will be atemperature that is greater than the target temperature, the turn-ontemperature, and/or the current temperature depending on the particularconfiguration. If the current temperature is less than the highthreshold temperature, the method 300 can include finishing 307 thecooling cycle and once again determining 302 whether the AC is on.

If the current temperature is greater than or equal to the highthreshold temperature, the method 300 can include determining 308whether the cooling cycle is complete. Determining 308 whether thecooling cycle is complete can include determining whether the AC hascompleted a cooling cycle and has shut down. Alternatively, or inaddition, determining 308 whether the cooling cycle is complete caninclude determining whether the current temperature is less than orequal to the turn-off temperature. If the cooling cycle is not complete,the method 300 can include continuing to check whether the cooling cycleis complete (e.g., continuously, at predetermined interval s).

If the cooling cycle is complete, the method 300 can include determining310 whether the capacity of the HVAC unit 114 at the time the coolingcycle was completed is greater than or equal to the threshold capacity.Determining 310 whether the capacity of the HVAC unit 114 at the timethe cooling cycle was completed is greater than or equal to thethreshold capacity can be substantially similar and include all of thesame features described in relation to feature 210 of method 200 exceptall features will be modified to apply to a cooling mode. For example,under normal conditions, the AC unit will begin to ramp down as theturn-off temperature is approached such that the AC unit will operate ata minimum capacity at or near the time of shutdown.

If the capacity of the HVAC unit 114 at the time the cooling cycle iscompleted is greater than or equal to the threshold capacity, the method300 can include adjusting 314 a response setting of the controller 130by a predetermined amount. Adjusting 314 the response setting can besubstantially similar to and include all of the same features describedin relation to adjusting 214 the response setting of method 200.

If the capacity of the HVAC unit 114 is less than the thresholdcapacity, the method 300 can include determining 312 whether a currenttemperature at the time the cooling cycle was completed is less than orequal to a low overshoot temperature. Similar to, but different from,feature 212 of method 200, determining 312 whether a current temperatureat the time the cooling cycle was completed is less than or equal to alow overshoot temperature can include determining whether the HVAC unit114 output too much cool air and, therefore, cooled the air within theclimate-controlled space too much. The low overshoot temperature can bea predetermined temperature that is indicative of the HVAC unit 114providing too much cooled air to the climate-controlled space 102. Forexample, if the turn-off temperature is 70° F., the low overshoottemperature can be 68° F. or some other predetermined temperaturesuitable for the application. In other words, if the current temperatureat the end of the cooling cycle (or sometime after the cooling cycle hascompleted) is less than the low overshoot temperature, it is possiblethat the thermostat 120 detected a temperature during the cooling cyclethat was not representative of the temperature of all or a substantialportion (e.g., the majority) of the air within the climate-controlledspace 102 (hence, why the HVAC unit 114 provided too much cooled air).

If the temperature at the end of the cooling cycle is greater than thelow overshoot temperature, the method 300 can include returning to thebeginning of method 300 and determining 302 whether the AC is on. If thetemperature at the end of the cooling cycle is less than or equal to thelow overshoot temperature, the method 300 can include adjusting 314 theresponse setting by the predetermined amount as described previously.

As will be appreciated, the methods 200 and 300 just described can bevaried in accordance with the various elements and examples describedherein. That is, methods in accordance with the disclosed technology caninclude all or some of the steps described above and/or can includeadditional steps not expressly disclosed above. Further, methods inaccordance with the disclosed technology can include some, but not all,of a particular step described above. Further still, various methodsdescribed herein can be combined in full or in part. That is, methods inaccordance with the disclosed technology can include at least someelements or steps of a first method (e.g., method 200) and at least someelements or steps of a second method (e.g., method 300).

While the present disclosure has been described in connection with aplurality of exemplary aspects, as illustrated in the various figuresand discussed above, it is understood that other similar aspects can beused, or modifications and additions can be made to the describedaspects for performing the same function of the present disclosurewithout deviating therefrom. For example, in various aspects of thedisclosure, methods and compositions were described according to aspectsof the presently disclosed subject matter. But other equivalent methodsor compositions to these described aspects are also contemplated by theteachings herein. Therefore, the present disclosure should not belimited to any single aspect, but rather construed in breadth and scopein accordance with the appended claims.

What is claimed is:
 1. A thermostat for a heating, ventilation, and airconditioning (HVAC) system comprising: a temperature sensor configuredto detect a temperature of air proximate the thermostat; and acontroller configured to: receive temperature data from the temperaturesensor; determine whether an amount of time since a heating cycle of anHVAC unit began is greater than or equal to a predetermined amount oftime; in response to determining that the amount of time since theheating cycle began is greater than or equal to the predetermined amountof time, determine whether a current temperature is less than or equalto a low threshold temperature, the low threshold temperature being lessthan a target temperature; in response to determining that the currenttemperature is less than or equal to the low threshold temperature,determine whether a capacity of the HVAC unit at the end of the heatingcycle is greater than a threshold capacity; and in response todetermining that the capacity of the HVAC unit at the end of the heatingcycle is greater than the threshold capacity, adjust a response settingof the thermostat by a predetermined adjustment amount.
 2. Thethermostat of claim 1, wherein the response setting is a gain setting ofthe controller.
 3. The thermostat of claim 2, wherein adjusting theresponse setting of the thermostat by the predetermined adjustmentamount comprises adjusting the gain setting of the controller by a fixedamount.
 4. The thermostat of claim 2, wherein adjusting the responsesetting of the thermostat by the predetermined adjustment amountcomprises adjusting the gain setting of the controller by an amount thatis proportional to the amount that the capacity of the HVAC unit at theend of the heating cycle is greater than the threshold capacity.
 5. Thethermostat of claim 1, wherein the response setting is a time setting ofthe controller.
 6. The thermostat of claim 5, wherein adjusting theresponse setting of the thermostat by the predetermined adjustmentamount comprises adjusting the time setting of the controller by a fixedamount.
 7. The thermostat of claim 5, wherein adjusting the responsesetting of the thermostat by the predetermined adjustment amountcomprises adjusting the time setting of the controller by an amount thatis proportional to the amount that the capacity of the HVAC unit at theend of the heating cycle is greater than the threshold capacity.
 8. Thethermostat of claim 1, wherein the low threshold temperature is lessthan a low turn-on temperature.
 9. The thermostat of claim 1, whereinthe controller is further configured to: in response to determining thatthe current temperature is less than or equal to the low thresholdtemperature, determine whether the current temperature at the end of theheating cycle is greater than or equal to a high overshoot temperature;and in response to determining that the current temperature at the endof the heating cycle is greater than or equal to the high overshoottemperature, adjust the response setting of the thermostat by thepredetermined adjustment amount.
 10. The thermostat of claim 9, whereinthe response setting is a gain setting of the controller.
 11. Thethermostat of claim 10, wherein adjusting the response setting of thethermostat by the predetermined adjustment amount comprises adjustingthe gain setting of the controller by a fixed amount.
 12. The thermostatof claim 10, wherein adjusting the response setting of the thermostat bythe predetermined adjustment amount comprises adjusting the gain settingof the controller by an amount that is proportional to the amount thatthe current temperature at the end of the heating cycle is greater thanthe high overshoot temperature.
 13. The thermostat of claim 9, whereinthe response setting is a time setting of the controller.
 14. Thethermostat of claim 13, wherein adjusting the response setting of thethermostat by the predetermined adjustment amount comprises adjustingthe time setting of the controller by a fixed amount.
 15. The thermostatof claim 13, wherein adjusting the response setting of the thermostat bythe predetermined adjustment amount comprises adjusting the time settingof the controller by an amount that is proportional to the amount thatthe current temperature at the end of the heating cycle is greater thanthe high overshoot temperature.
 16. The thermostat of claim 1, whereinthe controller is further configured to: determine whether an amount oftime since a cooling cycle of an HVAC unit began is greater than orequal to the predetermined amount of time; in response to determiningthat the amount of time since the cooling cycle began is greater than orequal to the predetermined amount of time, determine whether the currenttemperature is greater than or equal to a high threshold temperature,the high threshold temperature being greater than the targettemperature; in response to determining that the current temperature isgreater than or equal to the high threshold temperature, determinewhether the capacity of the HVAC unit at the end of the cooling cycle isgreater than the threshold capacity; and in response to determining thatthe capacity of the HVAC unit at the end of the cooling cycle is greaterthan the threshold capacity, adjust a response setting of the thermostatby a predetermined adjustment amount.
 17. The thermostat of claim 16,wherein the high threshold temperature is greater than a high turn-ontemperature.
 18. The thermostat of claim 17, wherein the controller isfurther configured to: in response to determining that the currenttemperature is less than or equal to the low threshold temperature,determine whether the current temperature at the end of the heatingcycle is greater than or equal to a high overshoot temperature; and inresponse to determining that the current temperature at the end of theheating cycle is greater than or equal to the high overshoottemperature, adjust the response setting of the thermostat by thepredetermined adjustment amount.
 19. The thermostat of claim 18, whereinthe response setting is a gain setting of the controller.
 20. Thethermostat of claim 18, wherein the response setting is a time settingof the controller.